Abstract: The accurate sensitive analysis of drugs in environmental samples, as well as the removal of these substances from natural and waste waters, is the great importance for maintaining viability. Sulfaguanidine is a widely used antibiotic. Registration of absorption and fluorescence spectra, spectra of pulsed cathodoluminescence in the region from 350 to 900 nm under irradiation with electron beams with a duration of 2 ns and an average energy of 170 keV was carried out to study the transformation of sulfaguanidine in water. It has been shown that this treatment of the solution results in the transformation of the sulfaguanidine molecule. Irradiation of the solution and excitation of pulsed cathodoluminescence of the boundary layer of air localized near the surface of the solution were carried out simultaneously by the same electron beam. The degree of antibiotic transformation under the action of an electron beam was determined from the change in the luminescence and absorption spectra of the irradiated solution. As a result, we recorded the utilization of dissolved sulfaguanidine, which means the neutralization of the solution. Thus, after electron irradiation, the toxicological effects of sulfonamide antibiotics decrease. © Pleiades Publishing, Ltd. 2023. ISSN 1062-8738, Bulletin of the Russian Academy of Sciences: Physics, 2023, Vol. 87, Suppl. 2, pp. S217–S221. Pleiades Publishing, Ltd., 2023.